/*
 *   This program is free software: you can redistribute it and/or modify
 *   it under the terms of the GNU General Public License as published by
 *   the Free Software Foundation, either version 3 of the License, or
 *   (at your option) any later version.
 *
 *   This program is distributed in the hope that it will be useful,
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *   GNU General Public License for more details.
 *
 *   You should have received a copy of the GNU General Public License
 *   along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

/*
 *    RemoveType.java
 *    Copyright (C) 2002-2012 University of Waikato, Hamilton, New Zealand
 *
 */

package weka.filters.unsupervised.attribute;

import java.util.Enumeration;
import java.util.Vector;

import weka.core.Attribute;
import weka.core.Capabilities;
import weka.core.Capabilities.Capability;
import weka.core.Instance;
import weka.core.Instances;
import weka.core.Option;
import weka.core.OptionHandler;
import weka.core.SelectedTag;
import weka.core.Tag;
import weka.core.Utils;
import weka.core.WeightedAttributesHandler;
import weka.core.WeightedInstancesHandler;
import weka.filters.Filter;
import weka.filters.StreamableFilter;
import weka.filters.UnsupervisedFilter;

/**
 * <!-- globalinfo-start --> Removes attributes of a given type.
 * <p/>
 * <!-- globalinfo-end -->
 * 
 * <!-- options-start --> Valid options are:
 * <p/>
 * 
 * <pre>
 * -T &lt;nominal|numeric|string|date|relational&gt;
 *  Attribute type to delete. Valid options are "nominal", 
 *  "numeric", "string", "date" and "relational".
 *  (default "string")
 * </pre>
 * 
 * <pre>
 * -V
 *  Invert matching sense (i.e. only keep specified columns)
 * </pre>
 * 
 * <!-- options-end -->
 * 
 * @author Richard Kirkby (rkirkby@cs.waikato.ac.nz)
 * @version $Revision$
 */
public class RemoveType extends Filter implements UnsupervisedFilter, StreamableFilter, OptionHandler, WeightedAttributesHandler, WeightedInstancesHandler {

    /** for serialization */
    static final long serialVersionUID = -3563999462782486279L;

    /** The attribute filter used to do the filtering */
    protected Remove m_attributeFilter = new Remove();

    /** The type of attribute to delete */
    protected int m_attTypeToDelete = Attribute.STRING;

    /** Whether to invert selection */
    protected boolean m_invert = false;

    /** Tag allowing selection of attribute type to delete */
    public static final Tag[] TAGS_ATTRIBUTETYPE = { new Tag(Attribute.NOMINAL, "Delete nominal attributes"), new Tag(Attribute.NUMERIC, "Delete numeric attributes"), new Tag(Attribute.STRING, "Delete string attributes"), new Tag(Attribute.DATE, "Delete date attributes"), new Tag(Attribute.RELATIONAL, "Delete relational attributes") };

    /**
     * Returns the Capabilities of this filter.
     * 
     * @return the capabilities of this object
     * @see Capabilities
     */
    @Override
    public Capabilities getCapabilities() {
        Capabilities result = super.getCapabilities();
        result.disableAll();

        // attributes
        result.enable(Capability.NOMINAL_ATTRIBUTES);
        result.enable(Capability.NUMERIC_ATTRIBUTES);
        result.enable(Capability.DATE_ATTRIBUTES);
        result.enable(Capability.STRING_ATTRIBUTES);
        result.enable(Capability.RELATIONAL_ATTRIBUTES);
        result.enable(Capability.MISSING_VALUES);

        // class
        result.enableAllClasses();
        result.enable(Capability.MISSING_CLASS_VALUES);
        result.enable(Capability.NO_CLASS);

        return result;
    }

    /**
     * Sets the format of the input instances.
     * 
     * @param instanceInfo an Instances object containing the input instance
     *                     structure (any instances contained in the object are
     *                     ignored - only the structure is required).
     * @return true if the outputFormat may be collected immediately
     * @throws Exception if the inputFormat can't be set successfully
     */
    @Override
    public boolean setInputFormat(Instances instanceInfo) throws Exception {

        super.setInputFormat(instanceInfo);

        int[] attsToDelete = new int[instanceInfo.numAttributes()];
        int numToDelete = 0;
        for (int i = 0; i < instanceInfo.numAttributes(); i++) {
            if (i == instanceInfo.classIndex()) {
                if (m_invert) {
                    attsToDelete[numToDelete++] = i; // Need to make sure to keep the class even if selection is inverted
                }
            } else if (instanceInfo.attribute(i).type() == m_attTypeToDelete) {
                attsToDelete[numToDelete++] = i;
            }
        }

        int[] finalAttsToDelete = new int[numToDelete];
        System.arraycopy(attsToDelete, 0, finalAttsToDelete, 0, numToDelete);

        m_attributeFilter.setAttributeIndicesArray(finalAttsToDelete);
        m_attributeFilter.setInvertSelection(m_invert);

        boolean result = m_attributeFilter.setInputFormat(instanceInfo);
        Instances afOutputFormat = m_attributeFilter.getOutputFormat();

        // restore old relation name to hide attribute filter stamp
        afOutputFormat.setRelationName(instanceInfo.relationName());

        setOutputFormat(afOutputFormat);
        return result;
    }

    /**
     * Input an instance for filtering.
     * 
     * @param instance the input instance
     * @return true if the filtered instance may now be collected with output().
     */
    @Override
    public boolean input(Instance instance) {

        return m_attributeFilter.input(instance);
    }

    /**
     * Signify that this batch of input to the filter is finished.
     * 
     * @return true if there are instances pending output
     * @throws Exception if something goes wrong
     */
    @Override
    public boolean batchFinished() throws Exception {

        return m_attributeFilter.batchFinished();
    }

    /**
     * Output an instance after filtering and remove from the output queue.
     * 
     * @return the instance that has most recently been filtered (or null if the
     *         queue is empty).
     */
    @Override
    public Instance output() {

        return m_attributeFilter.output();
    }

    /**
     * Output an instance after filtering but do not remove from the output queue.
     * 
     * @return the instance that has most recently been filtered (or null if the
     *         queue is empty).
     */
    @Override
    public Instance outputPeek() {

        return m_attributeFilter.outputPeek();
    }

    /**
     * Returns the number of instances pending output
     * 
     * @return the number of instances pending output
     */
    @Override
    public int numPendingOutput() {

        return m_attributeFilter.numPendingOutput();
    }

    /**
     * Returns whether the output format is ready to be collected
     * 
     * @return true if the output format is set
     */
    @Override
    public boolean isOutputFormatDefined() {

        return m_attributeFilter.isOutputFormatDefined();
    }

    /**
     * Returns an enumeration describing the available options.
     * 
     * @return an enumeration of all the available options.
     */
    @Override
    public Enumeration<Option> listOptions() {

        Vector<Option> newVector = new Vector<Option>(2);

        newVector.addElement(new Option("\tAttribute type to delete. Valid options are \"nominal\", \n" + "\t\"numeric\", \"string\", \"date\" and \"relational\".\n" + "\t(default \"string\")", "T", 1, "-T <nominal|numeric|string|date|relational>"));

        newVector.addElement(new Option("\tInvert matching sense (i.e. only keep specified columns)", "V", 0, "-V"));

        return newVector.elements();
    }

    /**
     * Parses a given list of options.
     * <p/>
     * 
     * <!-- options-start --> Valid options are:
     * <p/>
     * 
     * <pre>
     * -T &lt;nominal|numeric|string|date|relational&gt;
     *  Attribute type to delete. Valid options are "nominal", 
     *  "numeric", "string", "date" and "relational".
     *  (default "string")
     * </pre>
     * 
     * <pre>
     * -V
     *  Invert matching sense (i.e. only keep specified columns)
     * </pre>
     * 
     * <!-- options-end -->
     * 
     * @param options the list of options as an array of strings
     * @throws Exception if an option is not supported
     */
    @Override
    public void setOptions(String[] options) throws Exception {

        String tString = Utils.getOption('T', options);
        if (tString.length() != 0) {
            setAttributeTypeString(tString);
        }
        setInvertSelection(Utils.getFlag('V', options));

        if (getInputFormat() != null) {
            setInputFormat(getInputFormat());
        }

        Utils.checkForRemainingOptions(options);
    }

    /**
     * Gets the current settings of the filter.
     * 
     * @return an array of strings suitable for passing to setOptions
     */
    @Override
    public String[] getOptions() {

        Vector<String> options = new Vector<String>();

        if (getInvertSelection()) {
            options.add("-V");
        }
        options.add("-T");
        options.add(getAttributeTypeString());

        return options.toArray(new String[0]);
    }

    /**
     * Returns a string describing this filter
     * 
     * @return a description of the filter suitable for displaying in the
     *         explorer/experimenter gui
     */
    public String globalInfo() {

        return "Removes attributes of a given type.";
    }

    /**
     * Returns the tip text for this property
     * 
     * @return tip text for this property suitable for displaying in the
     *         explorer/experimenter gui
     */
    public String attributeTypeTipText() {

        return "The type of attribute to remove.";
    }

    /**
     * Sets the attribute type to be deleted by the filter.
     * 
     * @param type a TAGS_ATTRIBUTETYPE of the new type the filter should delete
     */
    public void setAttributeType(SelectedTag type) {

        if (type.getTags() == TAGS_ATTRIBUTETYPE) {
            m_attTypeToDelete = type.getSelectedTag().getID();
        }
    }

    /**
     * Gets the attribute type to be deleted by the filter.
     * 
     * @return the attribute type as a selected tag TAGS_ATTRIBUTETYPE
     */
    public SelectedTag getAttributeType() {

        return new SelectedTag(m_attTypeToDelete, TAGS_ATTRIBUTETYPE);
    }

    /**
     * Returns the tip text for this property
     * 
     * @return tip text for this property suitable for displaying in the
     *         explorer/experimenter gui
     */
    public String invertSelectionTipText() {

        return "Determines whether action is to select or delete." + " If set to true, only the specified attributes will be kept;" + " If set to false, specified attributes will be deleted.";
    }

    /**
     * Get whether the supplied columns are to be removed or kept
     * 
     * @return true if the supplied columns will be kept
     */
    public boolean getInvertSelection() {

        return m_invert;
    }

    /**
     * Set whether selected columns should be removed or kept. If true the selected
     * columns are kept and unselected columns are deleted. If false selected
     * columns are deleted and unselected columns are kept.
     * 
     * @param invert the new invert setting
     */
    public void setInvertSelection(boolean invert) {

        m_invert = invert;
    }

    /**
     * Gets the attribute type to be deleted by the filter as a string.
     * 
     * @return the attribute type as a String
     */
    protected String getAttributeTypeString() {

        if (m_attTypeToDelete == Attribute.NOMINAL) {
            return "nominal";
        } else if (m_attTypeToDelete == Attribute.NUMERIC) {
            return "numeric";
        } else if (m_attTypeToDelete == Attribute.STRING) {
            return "string";
        } else if (m_attTypeToDelete == Attribute.DATE) {
            return "date";
        } else if (m_attTypeToDelete == Attribute.RELATIONAL) {
            return "relational";
        } else {
            return "unknown";
        }
    }

    /**
     * Sets the attribute type to be deleted by the filter.
     * 
     * @param typeString a String representing the new type the filter should delete
     */
    protected void setAttributeTypeString(String typeString) {

        typeString = typeString.toLowerCase();
        if (typeString.equals("nominal")) {
            m_attTypeToDelete = Attribute.NOMINAL;
        } else if (typeString.equals("numeric")) {
            m_attTypeToDelete = Attribute.NUMERIC;
        } else if (typeString.equals("string")) {
            m_attTypeToDelete = Attribute.STRING;
        } else if (typeString.equals("date")) {
            m_attTypeToDelete = Attribute.DATE;
        } else if (typeString.equals("relational")) {
            m_attTypeToDelete = Attribute.RELATIONAL;
        }
    }

    /**
     * Main method for testing this class.
     * 
     * @param argv should contain arguments to the filter: use -h for help
     */
    public static void main(String[] argv) {
        runFilter(new RemoveType(), argv);
    }
}
